Installation · 6 min read
Sputter Film Installation on Tempered, Laminated, and Annealed Glass
Sputter film installs differently on each glass type. The same crew on the same building will encounter all three glass varieties (curtain wall typically uses tempered + laminated, interior glazing is often annealed). Here's what changes — and what stays the same — between substrates.
Annealed glass
Annealed (also called "float") glass is the standard untreated soda-lime float glass. Most common on interior partitions, low-rise commercial, and older legacy buildings.
Installation specifics
- Thermal stress: lowest of the three glass types. Annealed glass tolerates ~40 °C delta-T before fracture risk.
- Edge handling: edges are typically not seamed or ground. Film should be cut 2–3 mm short of the glass edge to avoid moisture wicking under.
- Application timing: standard wet-installation. Activator solution applied at room temperature, film positioned within 60 seconds.
- Cure time: 7–14 days to full adhesion. Avoid cleaning during this period.
Common failures
Annealed glass installs are generally trouble-free. The most common issue is edge lift after 12–24 months due to under-cut film at the glass edge — a workmanship issue, not a film issue.
Tempered glass
Tempered glass is heat-treated for 4–5× the strength of annealed. Required by code for any glazing within 18" of a door or floor, and standard for curtain wall.
Installation specifics
- Thermal stress: highest of the three. Tempered glass tolerates ~250 °C delta-T before fracture, but the addition of sputter film raises absorbed solar load — thermal stress analysis required for darker tints (sputter Max series at < 15% VLT on tempered glass needs special review).
- Edge handling: tempered glass edges are typically polished or seamed. Cut film 1–2 mm short of edge.
- Application timing: standard wet-installation. Tempered glass surface has some compressive stress that affects activator dwell time — extend by 15 seconds vs annealed.
- Cure time: 10–14 days to full adhesion.
- Important: tempered glass cannot be cut after manufacturing. Any film application error on tempered glass requires replacing the glass, not the film.
Common failures
The catastrophic failure on tempered glass is thermal fracture — when the film raises absorbed solar load above the tempered glass's stress tolerance. This is rare with LUNOX sputter (we run thermal analysis upfront) but does happen with under-engineered installations. The signature is a clean radial crack pattern, usually triggered on the first hot summer day post-install.
Laminated glass
Laminated glass is two or more glass plies bonded with a PVB (polyvinyl butyral) or SGP (SentryGlas) interlayer. Standard for safety glazing, overhead glass, and curtain wall infill.
Installation specifics
- Thermal stress: more complex than annealed or tempered. The interlayer absorbs some heat and creates a temperature gradient through the laminate. Sputter film on the inboard surface can drive the outer ply temperature 10–15 °C higher than uncoated — within tolerance for most laminated glass but worth analyzing.
- Edge handling: laminated edges show the PVB interlayer — installers must avoid getting activator solution on the interlayer (causes haze). Cut film 3–4 mm short of edge.
- Application timing: standard wet-installation. PVB interlayer is sensitive to solvent solvents — use only LUNOX-approved activator solution.
- Cure time: 14–21 days to full adhesion. Longer than tempered or annealed because heat dissipation through laminated glass is slower.
Common failures
The most common laminated-glass failure is PVB delamination at the edges — typically triggered by activator solvent infiltrating between the PVB and outer glass ply. LUNOX-certified installers know to cut shorter and dry the edges before applying. Non-certified installers using generic solutions cause this regularly.
Side-by-side install reference table
| Annealed | Tempered | Laminated | |
|---|---|---|---|
| Edge clearance | 2–3 mm | 1–2 mm | 3–4 mm |
| Activator dwell time | standard | +15 sec | standard |
| Full cure time | 7–14 days | 10–14 days | 14–21 days |
| Thermal stress risk | low | medium (analyze) | medium-high (analyze) |
| Catastrophic failure mode | edge lift | thermal fracture | PVB delamination |
Inspection criteria — what to look for at handover
- No visible bubbles, creases, or trapped debris at standard observation distance (typically 2 meters at 90° to glass).
- Edge consistency: cut line straight, 1–4 mm clearance as appropriate for substrate.
- No fingerprints or smears on the film surface. Reflective sputter shows fingerprints prominently.
- Color uniformity across the full installation. Lot-to-lot variation in sputter film should be controlled at the QC stage; if you see visible color steps between panes, that's an unintentional lot mix.
- Spec-conformant samples retained: every installation should retain a 30 cm × 30 cm sample from the parent roll for warranty reference.
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